I n 1889, the year of his death, Robert Browning made a recording of his voice at a dinner party given by his friend, the artist Rudolf Lehmann. One of the other guests had brought with him a phonograph, and although Browning at first declined to speak into it, he was eventually prevailed upon to recite some lines from one of his most popular poems, "How they brought the Good News from Ghent to Aix".

You can hear Browning's party piece on a recent British Library CD of historic recordings from its sound archive. The sound quality is poor - it was, after all, just 12 years since the invention of Edison's tinfoil cylinder machine - but through the hiss and crackle, it's just possible to make out the surprisingly high-pitched warblings of an elderly gent who, after the first couple of lines, is stumped by failing memory and forced to announce, "I'm terribly sorry but I can't remember me own verses." His embarrassment is covered by the cheering of the other guests as the recording fades.

In the latter part of his life, following his return to England from Italy after the death of his wife Elizabeth Barrett Browning in 1861, Robert Browning became well known as a party animal in London drawing-rooms, as much loved as despised for his powers as a raconteur and for his "afternoon-tea" manner. At these gatherings, according to one newspaper, no one would have suspected him of poetry for he looked like a rich banker. A contemporary described his talk as being "already in full flood at a distance of twenty feet", while Mary Gladstone objected to the way he "puffs and blows and spits in your face".

What Thomas Hardy once called "The Riddle of Browning" was famously taken up by Henry James. In his story "The Private Life", James dramatised what he perceived as Browning's essential duality: the public façade of the well-dressed socialite, talkative though giving little away, and the inscrutable private personage of the poet of genius. Most of Browning's biographers have followed this lead in their representation of his two divided, "dissociated", selves, and while his latest biographer, Iain Finlayson, ambitiously subtitles his book "A Private Life", his biography is as much an amalgam of "the pair of independent compartments", as James called them, as its predecessors.

The chances of making any dramatic new discoveries are, in any case, slight. In his final years Browning was well aware "of the unscrupulous hunger for old scandals", and two years before his death he spent a week reducing many of his personal papers, including drafts of his work and his entire collection of letters to his family, to a heap of ashes. The one set of correspondence he couldn't bear to destroy was the letters between him and Elizabeth from their courtship to her death. Her letters, he wrote, "would glorify the privileged receiver beyond any imaginable crown in the world or out of it..."

They provide a vital resource for the biographer and Finlayson's book is full of them. Overstuffed, in fact, with letters from an enormous range of correspondents. Early on Finlayson confesses a weakness for the format of the Victorian Life and Letters, and this soon becomes obvious as page after page is filled with great blocks of quotation. He also insists on indulging in lengthy dialogues with previous biographers of Browning like Alexandra Sutherland Orr and GK Chesterton. At 758 pages this book is a real wrist-wrecker and unnecessarily long, which is a pity because Finlayson is a thorough and highly intelligent biographer who - when he has the confidence to forego his dependence on other people's opinions - reveals an enviable talent for writing rich and moving narrative.

Finlayson has another problem - Browning's work and its reputation for obscurity. Born in 1812 and brought up in Camberwell amid his father's collection of 6,000 books, Browning published his first poem, Pauline, anonymously in 1833. After writing for the theatre as a result of his friendship with Macready, he published a narrative poem, Sordello, in 1840, which effectively left a question mark hanging over his literary career for the next 20 years. Tennyson said that the only lines he understood were the first and the last - "Who will, may hear Sordello's story told" and "Who would, has read Sordello's story told" - and 15 years later, after the appearance of Browning's Men and Women, George Eliot's remark that "what we took for obscurity in him was superficiality in ourselves" was only a more generous restatement of an attitude of general incomprehension.

There was some doubt whether Browning himself remembered the source of many of his poetry's allusions. Henry James was comforted on hearing Browning read his poems to find that "at least, if you don't understand them, he apparently understands them even less." One of the disadvantages about reading Browning today is that his power is only really apparent when he is read in bulk. Finlayson makes a good case for Browning both as a major transitional voice, and as a High Victorian commentator in verse on science, the higher criticism of scripture, spiritualism and other preoccupations of the age.

But it is the love story at the centre of Browning's life that gives this new biography its heartbeat as it did his greatest poetry. Robert's elopement to Italy with the morphine-addicted Miss Barrett, together with her maid Wilson and dog Flush (who bit Browning twice), was the literary romance that warmed the hearts of their contemporaries as much as those of succeeding generations. (Wordsworth was more sanguine about it. "I hope they may understand one another," he said. "Nobody else could.") Perhaps it does Browning's reputation some good that he will ever be identified in the popular imagination with the dashing romantic profile of Frederic March in the 1934 film version of Rudolph Besier's play The Barretts of Wimpole Street. This also starred MGM's grande dame Norma Shearer as a squint-eyed, wilting Elizabeth and an ogreish Charles Laughton positively chewing up the scenery in the role of Mr Barrett (the less said about the 1960s musical Robert and Elizabeth, and its song "Pass the Eau de Cologne", the better). Certainly the real Browning was ever the dandy, posing in a soft blue shirt while writing letters to Elizabeth, and wearing a smart green jacket on one of their 91 meetings before their wedding day at St Marylebone Parish Church in the autumn of 1846.

Elizabeth entrusted her future to Browning and he didn't betray her. As Chesterton said, Browning's secret marriage was his one unconventional act in a conventional life. Yet it took a different kind of flouting of convention for Browning to support so unresentfully his wife's claim over his to be the great poetic voice of the 1850s. After her death, the burden of expectation passed to their only child, Robert Weidemann Barrett Browning, known as Pen. Pen who, as a baby, had to be wrested from his mother's breast with the taste of bitter aloes, and who continued to sleep in his mother's room until he was 12, provided the main focal point for Browning's remaining few decades. He ended up as a wonderfully prosaic character for the offspring of two poets, metamorphosing from a disturbingly androgynous child, all in ringlets and silks, into a beefy and beery middle-aged man in knickerbockers, with a reputation for promiscuity and a home nicknamed "Palazzo Pigsty".

He was a faithful guardian, however, of his parents' memory, though when Browning died in 1889, Pen could not bear the thought of his mother's bones in Italy being disinterred for burial with his father in England. Instead, Browning had a funeral on a national scale in Westminster Abbey, and the Barrett-Browning romance was remembered by the singing of her poem, "What would we give to our beloved?". But, in spirit, as Browning had written some years earlier, his heart would always lie buried with Elizabeth in the Protestant Cemetery in Florence.